1. Department of Obstetrics and Gynecology; Aarhus University Hospital; Aarhus Denmark
2. Department of Clinical Medicine; Aarhus University; Aarhus Denmark
3. Department of Clinical Epidemiology; Aarhus University Hospital; Aarhus Denmark
4. Department of Epidemiology; Johns Hopkins Bloomberg School of Public Health; Baltimore MD USA
5. Department of Global Health; George Washington University; Washington DC USA